Magnetic stator cores for turbine generators typically include radially oriented slots that extend axially along the length of the core. Armature windings are seated within the slots and are held in place by a slot support system that includes tapered stator dovetail wedges and slides, various solid and conforming fillers, and a top ripple spring. These support components are employed in order to maintain the stator armature windings in a radially tight condition within the slots. The tapered dovetail wedges are received within axial dovetail slots on opposite side walls of the radial slots. During the process of tightening the stator wedges, it is necessary to install a complementary-shaped, tapered wedge slide against each stator wedge. For the sake of convenience, reference will be made herein to xe2x80x9cstator wedgesxe2x80x9d that are seated in the dovetail slots and xe2x80x9cstator slidesxe2x80x9d that are used to tighten the wedges. The stator slide is pre-gauged and pre-sized to have a significant interference fit relative to the slot contents, i.e., the windings, fillers and ripple springs. The force required to install the stator slide may be several thousand pounds.
Several methods have been used to provide force required to install the stator slides. For example, stator slides have been manually installed using a drive board and a large hammer, and using a modified pneumatically operated riveting gun. These methods, however, are time consuming and place considerable strain on the operator. They also subject the operator to the risk of repetitive motion injury and/or hearing damage, and pose a risk to the integrity of the stator core and armature windings.
This invention provides a new user-friendly stator slide driver device that provides a smooth, controlled, non-impacting stator slide assembly technique, with significant reduction or elimination of the aforementioned risks.
More specifically, this invention provides a stator slide driver tool that utilizes a predisposed hole in an adjacent already tightened stator wedge to provide the reaction point for the stator slide driving force. In one exemplary embodiment, a commercially available air wrench is secured to a tool frame and utilized to drive a lead screw which, in turn, causes a force application cart, mounted for movement along elongated rails of the tool frame, to move axially in one of two directions, depending on the direction of rotation of the lead screw. The tool includes an adjustable pin, spaced axially from the cart, and adapted to be received in a hole in the adjacent and already tightened stator wedge. In use, the cart is located so that an upstanding flange of a drive block abuts the rearward end of a stator slide loosely located under a stator wedge adjacent an already tightened stator wedge in which the pin is inserted. Actuation of the air wrench will cause the cart and its force application flange to drive the stator slide under the stator wedge, without repetitive impact, to thereby tighten the wedge, using the adjacent already tightened wedge as a force reaction point.
In a preferred embodiment of the invention, triggers for actuating and operating the air wrench are located on the respective handles provided at opposite ends of the elongated rails. Specifically, a first trigger on one of the handles is an on/off device while a second trigger on the other of the handles is a forward/reverse device. Both triggers incorporate pneumatic valves that control their respective functions. This arrangement allows the tool to be utilized by a single operator.
Another feature of the invention includes the provision for a 90xc2x0 swivel fitting connecting an air supply hose to the air wrench. The swivel fitting rotates a full 360xc2x0, thus allowing the operator to move the hose as necessary to avoid interference, e.g., to have the fitting point down and away from the operator during the wedge tightening process.
Accordingly, in one aspect, the present invention relates to a tool for driving a stator slide under a stator wedge within a radial slot of a stator core comprising a frame including a pair of elongated rail members, the frame provided with a pair of handles at respective opposite ends of the elongated rail members; a force application cart located between the rail members, the force application cart having a drive block thereon; a drive connected to the frame, substantially intermediate opposite ends of the frame, the drive having an on/off trigger located on one of the handles; and a lead screw threadably engaged at one end with the force application cart and connected at an opposite end to the drive such that the drive rotates the lead screw when actuated; wherein, in use, rotation of the lead screw causes axial movement of the force application cart and the drive block along the elongated rail members.
In another aspect, the invention relates to a tool for driving a stator slide under a stator wedge within a radial slot of a stator core comprising a frame including a pair of elongated rail members, the frame provided with a pair of handles at respective opposite ends of the elongated rail members; a force application cart located between the rail members, the force application cart having a drive block thereon; an air wrench connected to the frame, substantially intermediate opposite ends of the frame, the air wrench having an on/off trigger located on one of the handles; and a lead screw threadably engaged at one end with the force application cart and connected at an opposite end to the air wrench such that the air wrench rotates the lead screw when actuated; wherein, in use, rotation of the lead screw causes axial movement of the force application cart and the drive block along the elongated rail members; and further including an air hose for supplying air to the air wrench, wherein the hose is connected to the air wrench with a swivel fitting.